Credible sets are sets of variants near a genetic association signal that are predicted, with a specific probability, to include the causal variant for that signal. These sets are generated by fine mapping, an additional step that is often applied to GWAS results to investigate in detail the region around a variant that is significantly associated with a phenotype. Several different methods are commonly used for fine mapping.
In the Knowledge Portals, we incorporate credible sets that accompany large GWAS, and we also use an automated method to calculate credible sets. See this page to browse and search the currently available credible sets.
Credible set membership of variants may be viewed in the Variant Sifter tool.